This invention relates generally to a construction tool and more particularly to an improved scoring and marking apparatus for a drywall or plasterboard sheet and similar sheet goods.
Numerous wallboard tools are known for use in wall construction employing prefabricated materials, such as gypsum plaster encased in paper or compressed wood fibers and chips, which are a substitute for plaster and wood panels. Heretofore, a number of patents and publications have disclosed tools for marking and cutting sheet goods such as drywall, the relevant portions of which are hereby incorporated by reference and may be briefly summarized as follows:
U.S. Pat. No. 5,048,189 to Aurness et al., issued Sep. 17, 1991 and U.S. Pat. No. 5,083,375 to Helm, Sr., issued Jan. 28, 1992, each disclose a drywall or wallboard cutter requiring a dedicated unit for adjusting and moving the cutter relative to the edge of a sheet.
U.S. Pat. No. 5,231,764 to Chang, issued Aug. 3, 1993, teaches a cutter for plasterboard sheet that may be affixed to a T-square. The cutter surrounds the elongated rule of the T-square and is retained thereon by a set screen impinging on the face of the elongated rule.
In a xe2x80x9cTrendlinesxe2x80x9d catalog, February 1998, p. 27, there is depicted a drywall scoring square.
In accordance with the present invention, there is provided a scoring apparatus for sheet goods, used in conjunction with a T-square, said apparatus comprising: a handle; a clamp, operatively associated with said handle, wherein said clamp is slidably moved along a blade of the T-square when the clamp and associated handle are in an open state and is frictionally locked to the T-square blade when the clamp and associated handle are in a closed state; and a scoring mechanism extending from the handle, said scoring mechanism being suitable for cutting at least a surface of the sheet as the T-square is moved relative to an edge of the sheet.
In accordance with another aspect of the present invention, there is provided a combination scoring and marking apparatus for sheet goods, used in conjunction with a T-square, said apparatus comprising: a handle including a recessed base, wherein the handle is suitable for grasping in the hand of a user; a clamp, operatively associated with said handle, wherein said clamp is slidably moved along a blade of the T-square when the clamp and associated handle are in an open state and is frictionally locked to the T-square blade when the clamp and associated handle are in a closed state, where the clamp may be moved between the open state and the locked state by a user using only one hand; a scoring mechanism associated with and extending from said handle, said scoring mechanism being suitable for cutting at least a surface of the sheet as the T-square is moved relative to an edge of the sheet.; and an adjustable holder for a marking device, connected to said handle, so as to allow the apparatus to mark a sheet as the T-square is moved relative to an edge of the sheet.
In accordance with yet another aspect of the present invention, there is provided a method of using a scoring apparatus for sheet goods, comprising: grasping the apparatus by a handle; sliding a clamp, operatively associated with said handle, over the end of a blade on a T-square; adjusting the apparatus to a desired position along the T-square blade; clamping the apparatus to the T-square blade by rotating the handle relative to the clamp, so that the clamp and is frictionally locked to the T-square blade; placing a head of the T-square adjacent an edge of the sheet goods; extending a scoring mechanism from said handle, said scoring mechanism being suitable for cutting at least a surface of the sheet; and drawing the T-square across the sheet goods so as to create a score thereon.
One aspect of the invention is based on the observation of problems with conventional tools used for the scoring, cutting and marking of sheet goodsxe2x80x94difficulty in use and the need for complex fixtures for attachment to conventional T-squares. This aspect is based on the discovery of a technique that alleviates these problems by providing a simple, yet reliable mechanism for the accurate attachment of the tool to a conventional T-square.
This technique can be implemented, for example, by a hinged clamp mechanism that locks the tool to the trunk of a T-square or similar device (e.g., L-square) by a simple rotation of the handle of the tool. On a simple motion a user can lock the tool and begin the scoring of marking of the sheet goods.
A machine implementing the invention can include a device or mechanism for scoring or cutting the sheet (e.g., a retractable knife blade) as well as a device for marking the sheet (e.g., a pencil holder), where the scoring and marking mechanisms are aligned relative to the sheet edge to enable a user to mark and score drywall and similar sheet goods in a consistent and accurate fashion.
The technique described above is advantageous because it is simple and inexpensive compared to other approaches. Furthremore, the device and method of use are adaptable for use with conventional T-squares and other measuring devices so as to make it unnecessary to purchase additional equipment. In addition to its direct application to use with drywall or plasterboard, it can be used to mark and score other types of sheet goods, including ceiling tile, insulation board, paneling, laminates, etc. The techniques of the invention are advantageous because they permit efficient construction of the tool, providing a reliable and accurate method for cutting and marking sheets without incurring the significant expense of an elaborate fixture. As a result of the invention, contractors and do-it-yourselfers will be able to quickly cut and mark sheet goods in a reliable and accurate fashion, thereby reducing wasted effort and materials.